no KANSAS UNIVERSITY QUARTERLY. 



tion" witli the tactile sense, it seems that a strong argument for 

 Berkeley's theor}^ has been found. But there have been a few peo- 

 ple of the above class to whom objects, when first seen, did not 

 appear in the same plane, but nearer and farther, although, of 

 course, experience enabled them to locate the objects more accu- 

 rately. 



The difficulty of finally settling the question of whether or not 

 distance is a visual as well as a tactile form of consciousness, is 

 greatly augmented by the fact that, although we find persons who 

 at one time perceived distance tactually, and later both factually 

 and visually, as above, we do not have at hand to compare with 

 them, persons who at first have no tactile sensations, but only 

 visual, and then later both kinds of sensations. 



Numerous experiments and observations have led psychologists 

 to conclude that distance perception may be regarded as the pro- 

 duct of three ever varying factors: retinal, muscular, and intellectual, 

 as may be seen in the following so-called "clues" — accommodation, 

 double and disparate images, difference in parallactic displacement 

 of objects when the head is moved, faintness of tint, dimness of 

 outline, and smallness of retinal images of objects named and 

 known, together with various comparisons and allowances made, 

 voluntarily and involuntarily. All of the above have sonietliing to 

 do with our notions of "far" and "near;'" but when we consider 

 that these -'aids" have a way of overcoming and overbalancing 

 each other, especially when influenced by the presence of some 

 other sensible quality in the object, anti that definite tactile and 

 retinal modifications do not accompany differences in distance, and 

 further, that there are many other irregularities, it then becomes 

 evident to us that the act of judging distance follows no simple 

 law. But that there are certain tendencies shown in our acts of 

 judgment, a number of psychological experiments have plainly in- 

 dicated; and it was to continue the examination of various estima- 

 tions of distance that the following investigation was made. The 

 accompanying drawing is intended to represent the large room in 

 which the tests of judging given distances were made, and to show 

 the mechanism and arrangement of the apparatus used. 



